Drain check in pressure regulator

ABSTRACT

A pressure regulator includes a housing having an inlet cap with an inlet flow passage and an outlet cap with an outlet flow passage. A plunger is reciprocally mounted in the housing. A stationary regulator valve seat is disposed between the inlet flow passage and an inlet to the plunger. A drain check shuttle is disposed in the inlet cap and positioned downstream of the regulator valve seat to prevent water from draining out of the regulator when an inlet water pressure is below a predetermined threshold.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent Application62/511,634 filed May 26, 2017, the entirety of which is incorporated byreference.

FIELD OF THE TECHNOLOGY

The invention relates to pressure regulators for liquid flow passages,and particularly to pressure regulators for supplying water toirrigation sprinklers and nozzles.

BACKGROUND

Irrigation systems often have several sprinklers and nozzles arrangedalong an extended water supply pipe. For example, a water supply pipe ina center pivot irrigation system may extend a quarter to half a mile(400 to 800 meters). The water supply pipe may have a diameter of six toten inches (152 to 254 millimeters) and provide water for over a hundredsprinklers or nozzles arranged along the pipe. Similarly, solid setirrigation systems may include long rows of plastic water supply pipesplaced between rows of crops with sprinklers on posts at regularlocations along the supply pipes. Each sprinkler or nozzle is typicallyconnected to the water supply pipe by a smaller water pipe that extendsvertically and includes a pressure regulator.

The sprinklers and nozzles are typically designed to receive water undera relatively low pressure and within a narrow pressure range. There is apressure regulator associated with each sprinkler or nozzle. Pressureregulators are typically placed in a water flow path and between a watersupply pipe and a sprinkler or nozzle. The pressure regulator maintainsa uniform water pressure flowing to the sprinkler or nozzle. Thepressure regulator ensures that the water pressure is within the designrange for the sprinkler or nozzle.

As a water supply pipe extends hundreds of meters, the pipe may riseover hills and drop into low points of an agricultural field. When flowto the water supply pipe is turned off, water collects at the low pointsin the pipe. The water at the low points drains out of the pipe andthrough the sprinklers or nozzles attached to the low points of thepipe, unless the sprinklers or nozzles have a drain check valve. Thedrainage of water may not be desired in some applications such as forcrops that do not tolerate temporary flooding. The concern of excessivewater on crops as water drains through sprinklers becomes greater forirrigation schedules that apply periodic bursts of water to the cropswith water turned off between bursts.

Drain check valves in pressure regulators are used to prevent water flowthrough the regulator when the pressure drops, e.g., is turned off, inthe water supply pipe. Prior art drain check valves are typicallydisposed at the outlet end of the regulator and typically includeradially extending ribs, support beams or spokes to support the valve.These support structures extend into the flow path creating obstructionsthat hinder flow through the regulator.

BRIEF SUMMARY

The inventors conceived and disclose herein a drain check shuttleincluded in a drain check valve for a pressure regulator that does notrequire supporting struts extending through the flow passage in theregulator. Without struts, the drain check shuttle and its supportstructure are less prone to catching debris, such as grasses, in thewater flowing through the pressure regulator.

A pressure regulator has been invented and is disclosed hereinincluding: a housing including a flow passage extending from an inlet,through the housing to an outlet; a plunger configured to movereciprocally within the housing along an axis of the plunger, whereinthe plunger is hollow and defines a passage included in the flow passageof the housing; a stationary regulator valve seat in the housing anddisposed between the inlet flow passage and an inlet to the plunger; andan annular drain check shuttle within the housing and configured to movereciprocally with respect to both the housing and the plunger, whereinthe drain check shuttle has a first position within the housing at whichthe drain check shuttle annularly abuts the regulator valve seat andcloses the flow passage and a second position displaced from theregulator valve seat and which opens the flow passage.

A pressure regulator has been invented and is disclosed herein thatincludes a housing including an inlet flow passage and an outlet flowpassage, the housing including an inlet cap having the inlet flowpassage and an outlet cap having the outlet flow passage, the inlet capand the outlet cap being connected to one another; a plungerreciprocally mounted in the housing; a stationary regulator valve seatdisposed between the inlet flow passage and an inlet to the plunger; anda drain check shuttle disposed in the inlet cap and positionedimmediately downstream of the regulator valve seat to prevent water fromflowing through the outlet flow passage when an inlet water pressure isbelow a predetermined threshold.

A pressure regulator has been invented and is disclosed herein thatincludes a housing having an inlet cap and an outlet cap connected toone another; a fluid passageway for conveying fluid through theregulator; a plunger reciprocally mounted in the housing; a stationaryregulator valve seat disposed between the inlet flow passage and aninlet to the plunger; and a drain check shuttle having an annular shapeincluding an outer wall positioned adjacent an inner side wall of thehousing and an inner wall delimiting a bore formed through the checkvalve shuttle, the plunger being slidably received in the bore, whereinthe fluid passageway includes an inlet flow passage in the inlet cap, aflow path through the plunger and an outlet flow passage in the outletcap.

Other aspects, features, and advantages of the disclosed and novel draincheck valve for a pressure regulator are apparent from the followingdetailed description when taken in conjunction with the accompanyingdrawings, which are a part of this disclosure and which illustrate, byway of example, principles of this technology.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an inlet side perspective view of a pressure regulator with anovel drain check valve;

FIG. 2 is an inlet side perspective view of the pressure regulator ofFIG. 1 shown in cross-section;

FIG. 3 is a cross-sectional view of the pressure regulator of FIG. 1showing the drain check shuttle valve in an initially closed position;

FIG. 4 is a cross-sectional view of the pressure regulator of FIG. 1showing the drain check shuttle in an open position, prior to pressureregulation of the outlet flow;

FIG. 5 is a cross-sectional view of the pressure regulator of FIG. 1showing the drain check shuttle valve in the open position and theplunger is in a position to regulate the outlet pressure;

FIG. 6 is an exploded view of the pressure regulator of FIG. 1 showingcomponents in cross-section;

FIG. 7 is an upstream perspective view of the annular drain checkshuttle of the pressure regulator shown in FIG. 1;

FIG. 8 is a downstream perspective view of the drain check shuttle ofFIG. 7;

FIG. 9 is a front view of the drain check shuttle of FIG. 7;

FIG. 10 is a cross-sectional view of the drain check shuttle along line10-10 in FIG. 9;

FIG. 11 is a graph showing outlet pressure versus inlet pressure of thepressure regulator with the novel drain check valve disclosed herein;

FIG. 12 is a perspective view of an inlet cap of the pressure regulatorshown in FIG. 1 with a portion of the inlet cap cut away;

FIG. 13 is an end view showing the outlet end of the inlet cap shown inFIG. 12; and

FIG. 14 is an end view showing the outlet end of the inlet cap shown inFIG. 12 having an internal vane to direct water flow.

DETAILED DESCRIPTION

FIGS. 1 and 2 show a flow-through type pressure regulator 10 inperspective and cross-sectional views respectively. The pressureregulator 10 includes a housing formed by an inlet cap 12 and an outletcap 14. The inlet and outlet caps are connected by a snap connection.The inlet cap 12 includes a connector 20 at an end portion therefore andthe outlet cap 14 includes a connector 22 at an end portion thereof, asshown in FIG. 2. Each connector 20, 22 has an inclined surface. Theinclined surfaces engage and slide relative to one another when theinlet cap and the outlet cap are pushed towards one another. Once theinclined surfaces slide past one another, each connector is received ina catch to securely connect the inlet cap 12 and the outlet cap 14.

The connector 20 of the inlet cap 12 presses against a ledge 68 of acylindrical liner 66 such that the liner is sandwiched between theconnector 20 and the outlet cap 14. A downstream rim 67 of the liner 66retains, e.g., clamps, an outer flange of diaphragm 40 against anannular rim 69 of the outlet cap 14. A secure connection between thediaphragm, inlet cap and outlet cap is needed to support the sprinklerassembly, avoid leakage of water from the pressure regulator and avoidseparation of the pressure regulator.

Referring to FIGS. 1 and 2, the inlet cap 12 includes an inlet flowpassage 24, and the outlet cap 14 includes an outlet flow passage 26.Ribs 25 on the inlet and outlet caps provide structural support for theinlet and outlet flow passages. The inlet and outlet flow passages mayhave threaded surfaces to receive water pipes (not shown) connected tothe pressure regulator. The water pipe connected to the inlet flowpassage provides water under pressure to the pressure regulator from awater supply pipe. A vertical water pipe (not shown) typically connectsthe pressure regulator to the water supply pipe. The outlet flow passage26 may be connected to a sprinkler assembly that hangs or is otherwisesupported by the pressure regulator.

FIGS. 3 to 5 show the pressure regulator 10 in cross section. FIG. 4shows a wide gap 27 in the flow passage through the regulator. FIG. 5shows a smaller gap that restricts the water passage. The pressureregulator 10 reduces the water pressure to maintain a constant waterpressure in the outlet flow passage 26, regardless of the water pressurein the inlet flow passage 24. Additionally, the pressure regulatorincludes an annular drain check shuttle 120 that blocks water frompassing through the pressure regulator when the water pressure in theinlet flow passage 24 is below a predetermined threshold. The draincheck shuttle 120 prevents water remaining in the water supply pipe fromdraining through the regulator while the inlet water pressure is belowthe predetermined threshold (e.g., when the irrigation system is off).FIG. 3 shows the drain check shuttle 120 in a closed position whereasFIGS. 4 and 5 show the drain check shuttle in an open position, as willbe later described in detail.

To maintain a uniform outlet water pressure, the pressure regulator 10widens or narrows the gap 27 depending upon the water pressure at theoutlet flow passage 26. The gap 27 is the most constricted portion ofthe flow passage in the pressure regulator. The width (see double arrowin FIG. 4) of the gap 27 adjusts automatically in response to the outletwater pressure. The gap 27 is widest while the water pressure in theoutlet flow passage 26 is no greater than a prescribed pressure level(FIG. 4). The prescribed pressure level may be set during the design ofthe pressure regulator and is dictated by the rate of the spring 38(also known as the spring constant). The gap 27 narrows (FIG. 5) if thewater pressure in the outlet flow passage 26 exceeds the prescribedpressure. Narrowing the gap 27 results in a corresponding reduction inwater pressure at the outlet 26 of the regulator.

The gap 27 is formed between an inlet 28 to a tubular plunger 30 and astationary regulator valve seat 32. The size of the gap 27 is determinedby the axial position of the plunger inlet 28 relative to the regulatorvalve seat 32. An annular section or circular disc of the regulatorvalve seat is sized to receive the circular inlet 28 to the plunger toclose the gap. The plunger 30 includes a cylindrical plunger passage 34for water flowing between the inlet flow passage 24 and the outlet flowpassage 26. The plunger 30 moves along its axis 36 within a short rangeof distances. The range of distances that the plunger moves correspondsto the gap 27. The movement of the plunger advances or retracts itsinlet 28 towards and away from the regulator valve seat 32.

A helical spring 38 biases, e.g., pushes, the plunger towards the outletcap 14 and away from the regulator valve seat 32. Water pressure in theoutlet flow passage 26 is substantially the same as the water pressurein a diaphragm chamber 39. The water pressure in the diaphragm chamberpushes the plunger towards the regulator valve seat by acting on aneffective annular area between the plunger passage 34 and convolution ofthe diaphragm 40 which is attached to the plunger. While the pressure inthe diaphragm chamber 39 is below the prescribed pressure level, thespring force applied to the plunger and diaphragm is greater than theforce due to water pressure applied to the diaphragm. The side of thediaphragm opposite to the outlet flow passage may be at an ambientpressure, which is achieved by venting the liner 66 to the atmospherethrough vent holes in the liner.

As the water pressure at the diaphragm chamber 39 increases beyond theprescribed pressure, the pressure applied to the diaphragm 40 overcomesthe spring force and moves the plunger 30 towards the regulator valveseat 32 to narrow the gap 27. The narrowing of the gap 27 reduces thewater pressure in the diaphragm chamber 39. The reduced water pressurelessens the pressure applied to the diaphragm 40 and allows the spring38 to retract the plunger 30 to widen the gap 27. The offsetting springforce and water pressure determine the width of the gap 27 and regulatethe water pressure at the diaphragm chamber 39.

Referring to FIGS. 3 to 6, the diaphragm 40 may be an annular, flexibleskirt secured to the plunger between a diaphragm retainer 41 and aplunger flange 43. The diaphragm retainer 41 may slide over the tube ofthe plunger and snap into a groove around the circumference of the tube.The plunger flange 43 may be integral with the tube of the plunger.Before the diaphragm retainer 41 is snapped in place on the tube of theplunger, the diaphragm 40 is placed between the plunger flange anddiaphragm retainer. The diaphragm is secured between the diaphragmretainer 41 and plunger flange 43, by snapping the diaphragm retainer onthe tube of the plunger. The diaphragm is secured to the housing of thepressure regulator by being clamped between the downstream rim 67 of theliner 66 and an annular rim 69 of the outlet flow cap 14.

A sealing element, e.g., a damper O-ring 47 is seated in the outlet cap14 and acts to dampen unwanted plunger oscillations which may otherwiseoccur under certain conditions (e.g., higher flow rates and/or highpressure differentials).

As shown in FIG. 4, the plunger 30 has an axis 36 offset from the axis42 of the inlet flow passage 24. The offset may be an angular offset 44in a range of about three to twelve and one-half degrees. Test indicatesthat angular offsets in a range of three to eight degrees, such fivedegrees, provide optimal regulator performance by minimizing turbulenceand nonuniform flow at the outlet of the regulator, suppressing cloggingof the gap by debris and minimizing pressure losses through theregulator.

The plunger axis 36 may intersect the axis 42 of the inlet cap near thedownstream end 46 of the plunger 30. Offsetting the plunger axis 36 iscontrary to most conventional approaches that align the axis of theplunger with the axes of the inlet and outlet flow passages.Intersecting the plunger axis 36, the end of the plunger aligns theoutlet of the plunger with the outlet flow passage, where the outletaxis 50 is coaxial with the inlet flow axis 42.

The axis 50 of the outlet flow passage 26 may be coaxial to the axis 42of the inlet flow passage 24. Having these axes 42, 50 coaxial minimizesforce moments applied to the pressure regulator by the inlet and outletwater pipes attached to the regulator. Having these axes 42, 50 coaxialalso assists in achieving vertical alignment along the inlet pipe,pressure regulator, outlet water pipe and the sprinkler. A sprinklertypically works best, e.g., when projecting a symmetrical water spraypattern, if its rotational axis is vertical.

FIG. 12 illustrates the inlet cap 12 in a perspective view with aportion of the cap cut away. A chamber 48 of the flow passage is shownsurrounding the regulator valve seat 32 and strut 54.

The strut 54 may be a single strut having an upstream surface 58, a nose60, and a back surface 62 that is generally parallel to the plunger axis36. The nose 60 and back surface 62 may form a generally cylindricalpost section of the strut extending downstream into chamber 48. Theupstream surface 58 of the strut slopes from the sidewall 52 of theinlet cap 12. The side edges of the upstream surface 58 extend to theback surface 62 of the strut. The strut may be embodied with variousshapes including the generally triangular shape attached to the sidewalland downstream post shown in FIG. 2. For example, the post section ofthe strut may be more pronounced than shown in FIG. 2. The strut extendsdownstream into the chamber 48, which is in contrast to mostconventional cantilevered-beam struts that extend solely radially intothe flow stream.

Referring to FIGS. 2 and 3, the upstream surface 58 of the strut may besmooth with a slight convex cross-sectional shape in a directionparallel to the plunger axis 36. The upstream surface 58 of the strutfacing the water flow is at a steep slope, such as at an angle in arange of twenty-five to fifty-five degrees. The steep slope of theupstream surface 58 deflects debris off the strut and into a gap (W1) ofthe flow chamber 48. Debris reaching the upstream surface 58 is swept bythe water flow along the upstream surface and off the nose 60 of thestrut.

The strut 54 may have a generally triangular shape and a downstream postas is shown in FIGS. 2-5. The apex of the triangle is integrated withthe inlet cap and is aligned with the sidewall of the inlet flow passage24. The legs of the triangle are formed by the upstream surface 58 andthe back surface 62 of the strut. The triangular shape provides a strongsupporting brace for the regulator valve seat 32, which is at the baseof the triangle. A triangular brace shape is suited to support theregulator valve seat and withstand a water flow, especially as comparedto a conventional cantilevered strut.

Referring to FIGS. 3-5, the chamber 48 may be formed between thesidewall 52 of the chamber 48, the outer surfaces of the regulator valveseat 32 and strut 54, and an upstream surface of the drain check shuttle120. Water enters the chamber 48 from the inlet flow passage 24 and,when the drain check shuttle is open (FIGS. 4 and 5), leaves the chamberby flowing into the plunger inlet 28. The chamber 48 surrounds theregulator valve seat 32 and strut 54, and has a larger cross sectionthan the cross section of the inlet flow passage 24. The large crosssection of the chamber 48 provides a relatively large volume of water toflow over and around the strut 54 and against the drain check shuttle(FIG. 3) or into the plunger inlet 28 (FIGS. 4 and 5). The distance (W1)between the nose 60 (also the front) of the strut and the sidewall 52may be substantially the same as the distance (W2) between the back ofthe strut and the sidewall 52. The large chamber 48 and thesubstantially equal distances (W1, W2) between the strut 54 and thesidewall 52 provide an open flow passage that is substantially free ofareas in the chamber where debris may be restricted. Further, thechamber 48 is free of radially projecting spokes, beams, ribs, vanes andother radially extending supports conventionally used for a regulatorvalve seat.

Offsetting the plunger axis 36 allows the strut 54 and regulator valveseat 32 to be shifted down into the expanded chamber 48. Due to theshift, the regulator valve seat and strut may be positioned closer toand integrated with the threaded sidewall 52 of the inlet flow passage24, as compared to a conventional cantilevered strut extending radiallyto the center of the flow passage.

The flow path through the inlet flow passage 24, through the chamber 48and into the plunger 30 is relatively uninterrupted and smooth. The flowpath may be free of radially extending support beams, ribs and spokesthat, if present, could disrupt the flow. The sloping upstream surface58 of the strut 54 extends from the sidewall of the inlet flow passage24 to the chamber 48 and further to the nose 60 of the strut.

The upstream surface 58 of the strut starts in or at the end of theinlet flow passage 24 and is upstream of the chamber 48. The upstreamsurface 58 starts radially inward of the sidewall of the chamber 48 dueto the angular offset 44 and as shown in FIG. 4. The upstream surface 58directs water into the chamber and around the strut. A portion of thewater flowing from the inlet flow passage 24 directly enters the chamber48, and does not directly contact the strut. Another portion of thewater flows over and around the upstream surface 58 to enter the chamberand around the back surface 62.

Water from the inlet flow passage 24 enters the chamber 48. Much of thewater flows through the front region (W1) of the chamber 48 and into theplunger while avoiding the strut. Avoiding the strut reduces the amountof turbulence created as the water flows through the chamber 48. Waterthat flows over the upstream surface 58 of the strut may be deflectedinto the plunger or may flow to the chamber back region (W2) behind thestrut. The water in the back region gap (W2) flows to gap 27 and intothe plunger. The shape of the chamber 48 and the relatively largeregions (W1, W2) contribute to minimizing turbulence and flow velocityvariations in the water flowing through the chamber 48 and into theplunger.

At least one vane or rib 64 (FIG. 14) in the region (W2) may be used todirect the flow towards the plunger and reduce turbulence in the flow.The vane 64 is optional and is not shown in the embodiments in FIGS. 1to 13. The vane 64 may be integral with the inlet cap and fixed to anoverhang 76 between the back surface 62 of the strut and the sidewall 52of the chamber. The vane deflects water flowing around the strut towardsthe plunger. The vane may be a planar rib, have an inverted V-shape oranother shape that deflects water towards the plunger.

The relatively large flow volume in the chamber 48 tends to reducefrictional losses in the water pressure. The frictional pressure lossmay be less than five (5) pounds per square inch (34 kPa) while thepressure regulator is operating at a maximum water flow. The reductionin the frictional pressure loss is due, in part, to the relatively highhydraulic diameter of the chamber 48. The hydraulic diameter is theratio of the cross-sectional area of the chamber 48 and the total lengthof the wetted perimeter of the chamber 48 and the strut at said crosssection.

Turbulence and velocity variations in the flow entering the plungersettle out as the water flows through the plunger passage. A plungerpassage 34 having a flow length equal to at least five diameters of thepassage is generally sufficient to settle turbulence and velocityvariations. The length of the plunger may also be selected such thataxis 36 of the plunger intersects the axis 50 of the outlet flow passage26 in the outlet cap.

As shown in FIG. 13, the regulator valve seat 32 may be an annularsurface 78 in a plane parallel to the inlet 28 of the plunger. A raisedridge 80 at the circumference of the annular surface 78 guides theplunger inlet 28 to the annular surface. The regulator valve seat andstrut may be generally hollow with supporting ribs 82 forming an X-bracewithin the hollow area of the strut.

As mentioned earlier, the pressure regulator includes a drain checkshuttle 120 to prevent drain out through the regulator (andcorresponding sprinkler) when the water pressure in the inlet flowpassage 24 is below a predetermined threshold (e.g., minimum operatingpressure). By this arrangement, water is held in the piping of theirrigation system when the system is off.

The drain check shuttle 120 may have a toroid or ring-shape including anouter circumferential wall 122 and an inner circumferential wall 124, asshown in FIGS. 6-10. A groove 123 is formed in the outer wall 122 andreceives a sealing element (e.g., an O-ring 143) therein. Alternatively,the sealing element may be a rolling diaphragm similar in structure todiaphragm 40. The inner wall 124 defines a bore through the drain checkshuttle and includes an upstream groove 125 and a downstream groove 127formed therein. Sealing elements (e.g., O-rings 145, 147) arerespectively received in the grooves 125, 127.

An upstream end 131 of the drain check shuttle 120 includes ridge 133encircling the bore and a pressing surface 132 positioned around theridge. A downstream end 135 of the drain check shuttle includes anannular recess 136.

Turning back to FIG. 3, the drain check shuttle 120 is shown in theclosed position. In this position, the O-ring 145 seals against theregulator valve seat 32 to prevent water from flowing past the shuttlevalve. The drain check shuttle 120 is urged into the closed positionedby a force exerted on the shuttle by spring 38 which is seated in therecess 136 (as shown in FIGS. 8 and 10) on the downstream side of theshuttle. In the closed position, the drain check shuttle 120 preventswater from draining out of the regulator when the irrigation system isoff.

The drain check shuttle 120 remains in the closed position until apredetermined water pressure threshold in the inlet flow passage 24 isexceeded. Water in the chamber 48 will exert a force against thepressing surface 132 of the drain check shuttle 120. When the force ofthe water on the pressing surface 132 exceeds the predetermined inletwater pressure value thereby overcoming the force of the spring 38, thedrain check shuttle will slide downstream relative to the housing, asshown in FIG. 4. The O-ring 143 forms a dynamic seal with the inner sidewall 52 of the inlet cap 14.

The liner 66 has a ledge 72 (or step) formed thereon which contacts thedownstream end 135 of the drain check shuttle 120 to limit axial travel(along axis 36) of the shuttle when the drain check is fully open.

As can be seen in FIG. 4, a gap is formed between the regulator valveseat 32 and the O-ring 145 and thus water may freely flow from chamber48 into the inlet 28 of the plunger 30. The drain check shuttle 120 nowprovides no obstructions to the flow path of the water. That is, thedrain check shuttle 120 is free of radially extending support beams,ribs, etc. that would extend into the flow path and disrupt the flow.

As the inlet water pressure increases, the plunger is moved in anupstream direction to narrow the gap 27 to regulate the outlet waterpressure, as shown in FIG. 5 and described above. The O-ring 147 forms adynamic seal with the plunger 30 to prevent water from flowingdownstream of the drain check shuttle 120 in an area between the valveand the plunger. As shown in FIG. 10, it will be noticed that the O-ring145 has a larger diameter (d1) than a diameter (d2) of the O-ring 147thereby allowing the plunger 30 to slide relative to the drain checkshuttle without contacting the O-ring 145.

Turning to FIG. 11, a graph representing the outlet water pressureversus the inlet water pressure of a pressure regulator such as shown inFIG. 1. The heavier line in FIG. 11 moves in the direction of increasingwater pressure at the inlet. The lighter line moves in the oppositedirection which is decreasing water pressure.

At point A, the inlet water pressure is below a predetermined thresholdand thus the drain check shuttle 120 is in the closed position (FIG. 3)to prevent water flow through the pressure regulator and cause theoutlet water pressure to be zero. From points A to B along the heavierline, the drain check shuttle 120 starts to open by moving downstreamtowards the open inlet end of the plunger. As the inlet water pressureincreases beyond the predetermined threshold (just beyond point B), thewater pressure applies a force against the drain check shuttle (in adirection of fluid flow) that is greater than the spring bias force(applied in an opposite direction of fluid flow). As the inlet waterpressure further increases, the plunger 30 begins to move towards theregulator valve seat 32, thus regulating the outlet flow's pressure(FIG. 5). As the inlet water pressure decreases (lighter weight line)from C to point B, the drain check shuttle remains in an open position.As the water pressure further decreases from points B to A, the draincheck shuttle moves upstream towards the regulator valve seat andannularly occludes the inlet of the plunger. While the drain checkshuttle is seated against the regulator valve seat, occluding the inletto the plunger (at point A and lower pressures along lighter weightline), the shuttle stops water flow towards the outlet of the pressureregulator.

The drain check shuttle may move quickly (see closeness of points A andB) between the closed and open position. The quick movement means thatthe drain check shuttle is effectively an on-off valve for the drainregulator.

The regulation of the flow through the pressure regulator is performedby the plunger and the regulator valve seat. As the water pressureincreases beyond the threshold needed to move the drain check shuttle,the increased pressure moves the diaphragm and shifts the plunger 30towards the regulator valve seat. The movement towards the regulatorvalve seat reduces the flow passage between the regulator valve seat andplunger and thereby holds constant (point C) the water pressure at theoutlet.

While at least one exemplary embodiment of the present invention(s) isdisclosed herein, it should be understood that modifications,substitutions and alternatives may be apparent to one of ordinary skillin the art and can be made without departing from the scope of thisdisclosure. This disclosure is intended to cover any adaptations orvariations of the exemplary embodiment(s). In addition, in thisdisclosure, the terms “comprise” or “comprising” do not exclude otherelements or steps, the terms “a” or “one” do not exclude a pluralnumber, and the term “or” means either or both. Furthermore,characteristics or steps which have been described may also be used incombination with other characteristics or steps and in any order unlessthe disclosure or context suggests otherwise. This disclosure herebyincorporates by reference the complete disclosure of any patent orapplication from which it claims benefit or priority.

The invention is:
 1. A pressure regulator comprising: a housingincluding a flow passage extending from a housing inlet, through thehousing to a housing outlet; a plunger configured to move reciprocallywithin the housing along an axis of the plunger, wherein the plunger ishollow and defines a plunger passage included in the flow passage of thehousing, the plunger passage including a plunger inlet at one end of theplunger and a plunger outlet at an opposite end of the plunger thatfaces the housing outlet, a regulator valve seat in the housing anddisposed between the housing inlet and the plunger inlet, wherein theregulator valve seat faces the plunger inlet; and a drain check shuttlewithin the housing and configured to move reciprocally with respect toboth the housing and the plunger, wherein the drain check shuttle has afirst position within the housing at which the drain check shuttle abutsthe regulator valve seat and closes the flow passage, and a secondposition displaced from the regulator valve seat and which opens theflow passage.
 2. The pressure regulator of claim 1 wherein the draincheck shuttle includes an annular structure having an outer perimeterconfigured to slidably engage the housing and an inner perimeterconfigured to receive and engage the regulator valve seat.
 3. Thepressure regulator of claim 2 wherein the inner perimeter of the draincheck shuttle is configured to slidably engage the plunger.
 4. Apressure regulator comprising: a housing including a flow passageextending from an inlet, through the housing to an outlet; a plungerconfigured to move reciprocally within the housing along an axis of theplunger, wherein the plunger is hollow and defines a passage included inthe flow passage of the housing; a regulator valve seat in the housingand disposed between the inlet to the flow passage and an inlet to theplunger; and a drain check shuttle within the housing and configured tomove reciprocally with respect to both the housing and the plunger,wherein the drain check shuttle has a first position within the housingat which the drain check shuttle abuts the regulator valve seat andcloses the flow passage, and a second position displaced from theregulator valve seat and which opens the flow passage; wherein the draincheck shuttle includes an opening supporting a first annular sealconfigured to engage the regulator valve seat and supporting a secondannular seal configured to engage the plunger; and wherein a diameter ofthe first annular seal is greater than a diameter of the second annularseal.
 5. A pressure regulator comprising: a housing including an inletflow passage and an outlet flow passage, the housing including an inletcap having the inlet flow passage and an outlet cap having the outletflow passage, the inlet cap and the outlet cap being connected to oneanother; a plunger reciprocally mounted in the housing, wherein theplunger includes a plunger passage and a plunger inlet; a regulatorvalve seat disposed between the inlet flow passage and the plungerinlet, wherein the regulator valve seat includes an annular surfacealigned with the plunger inlet along an axis of the plunger passage, andthe plunger has a first position at which the plunger inlet is spacedapart from the annular surface of the regulator valve seat and a secondposition in which the plunger inlet is adjacent the annular surface ofthe regulator valve seat; and a drain check shuttle disposed in theinlet cap, the drain check shuttle being positioned downstream of theregulator valve seat and configured to prevent an incoming water flowfrom flowing through the outlet flow passage when an inlet waterpressure is below a predetermined threshold.
 6. The pressure regulatorof claim 5, wherein the drain check shuttle is arranged to slide alongan inner side wall of the inlet cap between a closed position in whichthe drain check shuttle seals against the regulator valve seat toprevent incoming water flow from entering the plunger passage and anopen position in which the drain check shuttle is displaced from theregulator valve seat to permit the incoming water flow to pass throughthe plunger passage to the outlet flow passage.
 7. The pressureregulator of claim 6, wherein the drain check shuttle includes apressing surface facing upstream and arranged to interface with theincoming water flow when the drain check shuttle is in the closedposition, and wherein once the inlet water pressure exceeds thepredetermined threshold, the pressing surface is adapted to receive aforce exerted thereon by the incoming water flow that causes the draincheck shuttle to slide into the open position.
 8. The pressure regulatorof claim 7, wherein the drain check shuttle is arranged to slide intothe open position against a force provided by a spring such that theforce exerted on the pressing surface by the incoming water flow exceedsthe force of the spring.
 9. The pressure regulator of claim 8, whereinthe spring is arranged to urge the drain check shuttle into the closedposition.
 10. The pressure regulator of claim 6, wherein the drain checkshuttle has a ring-shape including an outer wall positioned adjacent theinner side wall of the inlet cap and an inner wall delimiting a boreformed through the drain check shuttle.
 11. A pressure regulatorcomprising: a housing including an inlet flow passage and an outlet flowpassage, the housing including an inlet cap having the inlet flowpassage and an outlet cap having the outlet flow passage, the inlet capand the outlet cap being connected to one another; a plungerreciprocally mounted in the housing; a regulator valve seat disposedbetween the inlet flow passage and an inlet to the plunger; and a draincheck shuttle disposed in the inlet cap, the drain check shuttle beingpositioned downstream of the regulator valve seat and configured toprevent an incoming water flow from flowing through the outlet flowpassage when an inlet water pressure is below a predetermined threshold;wherein the drain check shuttle is arranged to slide along an inner sidewall of the inlet cap between a closed position in which the drain checkshuttle seals against the regulator valve seat to prevent incoming waterflow from passing the drain check shuttle and an open position in whichthe drain check shuttle is displaced from the regulator valve seat topermit the incoming water flow to pass through the regulator to theoutlet flow passage; wherein the drain check shuttle has a ring-shapeincluding an outer wall positioned adjacent the inner side wall of theinlet cap and an inner wall delimiting a bore formed through the draincheck shuttle; and wherein the drain check shuttle includes a firstO-ring disposed in the inner wall of the drain check shuttle, the firstO-ring arranged to seal against the regulator valve seat when the inletwater pressure is below the predetermined threshold.
 12. The pressureregulator of claim 11, wherein a gap is formed between the regulatorvalve seat and the first O-ring when the drain check shuttle is in theopen position to permit the incoming water flow to pass through thepressure regulator.
 13. The pressure regulator of claim 12, wherein thedrain check shuttle includes a second O-ring disposed in the inner wallof the drain check shuttle downstream of the first O-ring, the secondO-ring arranged to form a dynamic seal with the plunger.
 14. Thepressure regulator of claim 13, wherein the drain check shuttle includesa third O-ring disposed in the outer wall of the drain check shuttle toform a dynamic seal with the inner side wall of the inlet cap, the thirdO-ring being configured to slide relative to the inner side wall of theinlet cap as the drain check shuttle slides between the closed positionand the open position.
 15. A pressure regulator comprising: a housingincluding an inlet of the housing to an outlet of the housing, wherein aflow passage through the pressure regulator extends from the inlet tothe outlet; a plunger reciprocally mounted in the housing; a plungerflow passage included in the flow passage and in fluid communicationwith the inlet and outlet; a regulator valve seat disposed between theinlet of the housing and an inlet to the plunger flow passage; aring-shaped drain check shuttle including an outer wall adjacent aninner side wall of the housing and an inner wall delimiting a borethrough the drain check shuttle, wherein the plunger is slidablyreceived in the bore; and an annular diaphragm coupling the plunger tothe housing, wherein the diaphragm forms a deformable seal between theoutlet of the housing and a chamber in the housing, a first side of theannular diaphragm is always in fluid communication with the outlet and asecond side, opposite to the first side, is always in fluidcommunication with the chamber.
 16. The pressure regulator of claim 15,wherein the drain check shuttle does not include ribs, spokes or supportbeams which extend into a fluid passageway extending from the inlet ofthe housing to the inlet of the plunger flow passage.
 17. The pressureregulator of claim 16, wherein the drain check shuttle is disposed in aninlet cap of the housing.
 18. The pressure regulator of claim 17,wherein the regulator valve seat is integral with the inlet cap of thehousing.
 19. The pressure regulator of claim 15, wherein the drain checkshuttle prevents incoming fluid flow from passing through the outlet ofthe housing when an inlet pressure is below a predetermined threshold.20. A pressure regulator comprising: a housing including an inlet of thehousing to an outlet of the housing; a plunger reciprocally mounted inthe housing; a plunger flow passage in fluid communication with theinlet and outlet; a regulator valve seat disposed between the inlet ofthe housing and an inlet to the plunger flow passage; and a ring-shapeddrain check shuttle including an outer wall adjacent an inner side wallof the housing and an inner wall delimiting a bore through the draincheck shuttle, wherein the plunger is slidably received in the bore;wherein the drain check shuttle prevents incoming fluid flow frompassing through the outlet to the housing when an inlet pressure isbelow a predetermined threshold; and wherein the drain check shuttleincludes a first O-ring disposed in the inner wall of the drain checkshuttle, and the first O-ring seals against the regulator valve seatwhile the inlet pressure is below the predetermined threshold.
 21. Thepressure regulator of claim 20, wherein the drain check shuttle ismovably disposed in the housing such that when the inlet pressure isabove the predetermined threshold, a gap is formed between the regulatorvalve seat and the first O-ring to permit the incoming fluid flow topass through the pressure regulator.
 22. The pressure regulator of claim20, wherein the drain check shuttle includes a second O-ring disposed inthe inner wall of the drain check shuttle downstream of the firstO-ring, the second O-ring arranged to form a dynamic seal with theplunger.
 23. The pressure regulator of claim 22, wherein the secondO-ring has a diameter that is smaller than a diameter of the firstO-ring.
 24. The pressure regulator of claim 22, wherein the drain checkshuttle includes a third O-ring disposed in the outer wall of the draincheck shuttle to form a dynamic seal with the inner side wall of thehousing.